JP2012076911A - Paper feed driving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feed driving apparatus which is more stabilized by lowering peak load by mitigating rapid load produced during engagement of an intermittent gear with a conveyance gear when a conveyance roller is started to rotate.SOLUTION: A second intermittent gear is joined to a first intermittent gear by an energizing means. When the first intermittent gear is started to rotate while being connected with a driving gear, the second intermittent gear joined to the first intermittent gear by the energizing means rotates. The toothed part of the second intermittent gear engages with the conveyance gear first to make the rotating direction of the conveyance gear the same as that of the first intermittent gear and then the first intermittent gear engages with the conveyance gear.

Description

The present invention relates to a sheet feeding drive device that feeds sheets one by one from a sheet storage unit such as a feeding cassette of an image forming apparatus such as a copying machine, a printer, and a facsimile machine, and rotates a conveyance roller and a separation roller that contacts the conveyance roller. The present invention relates to a paper feed driving device including a transmission device.

In an image forming apparatus such as a copying machine, a printer, or a facsimile machine, a conveyance roller that is driven in a sheet feeding direction and a conveyance roller are disposed opposite to the conveyance roller and driven with a predetermined rotational torque in a direction opposite to the feeding direction. 2. Description of the Related Art A sheet feeding / separating apparatus that feeds and separates sheet paper using a separation roller is known.

The sheet feeding drive unit used in this type of sheet feeding / separating apparatus uses a plurality of idler gears to rotate the drive gear connected to a drive source such as a main body motor, and the separation roller is rotated in the direction opposite to the sheet feeding direction. It is transmitted to the reverse gear that rotates. On the other hand, the rotation of the drive gear is transmitted to the transport gear that intermittently rotates the transport roller in the paper feeding direction at a predetermined timing via the missing gear.

This will be described in more detail with reference to FIG.
The sheet accommodated in the sheet feeding cassette is conveyed toward the nip portion between the conveying roller 1 and the separation roller 2 from the left side of the drawing by a pickup roller (not shown).
The separation roller 2 rotates in a direction opposite to the paper feeding direction with a torque limiter 3 that generates a predetermined torque interposed therebetween. A reverse gear 4 fixed to the rotation shaft of the separation roller 2 is rotated from the drive gear 6 via an idler gear 5.

On the other hand, the conveyance roller 1 rotates in the paper feeding direction opposite to the separation roller 2 at a predetermined timing in response to the operation of the pickup roller (not shown). The intermittent rotation control is interposed between the drive gear 6 and the transport gear 7, and has a toothless portion for interrupting the drive from the drive gear 6 and a transmission for transmitting the drive from the drive gear. Conveying toothless gear 11 having a toothed portion, and configured to be coaxially integrated with the conveying toothless gear 11, and transmit the drive to and from the toothless portion for blocking driving from the driving gear 6 to the conveying gear 7. A first toothless gear 12 having a toothed portion is provided. The conveying toothless gear 11 is engaged with the engaging portion provided on the conveying toothless gear 11 and is stopped at a predetermined position.

In response to the operation electric signal, the operation of the solenoid 8 that releases the engagement state causes the rotation starting means 9 to release the conveyance missing gear 11 from the stopped state and rotate the conveyance missing gear 11 from the stop position. And mesh with the drive gear 6.

The operation of the transport roller 1 will be described.
First, when the solenoid 8 is energized at a predetermined timing according to the operation timing of the pickup roller (not shown), the conveying toothless gear 11 starts to rotate by the urging force of the rotation starting means 9, and the drive gear 6 Mesh with. Next, when a predetermined angle is rotated, the first toothless gear 12 rotating integrally with the conveying toothless gear 11 meshes with the conveying gear 7, rotates the conveying roller 1, and conveys the sheet.

When the sheet is conveyed for a predetermined distance, the meshing of the conveying gear 7 is completed at the toothed portion of the first intermittent gear 12. Thereafter, the meshing of the conveying gear is completed with the drive gear 6, and the engaging portion provided in the conveying gear 11 is engaged with the solenoid 8 and stops rotating.
JP 2004-115201 A

However, in the conventional sheet feeding drive device as described above, the separation roller 2 is in reverse contact until the conveyance roller 1 is rotated by the conveyance gear 7 after the sheet is fed, so that the separation roller 2 rotates in reverse. As a result, the transport roller 1 rotates while having a predetermined torque (depending on the retard torque limiter) in a direction opposite to the paper feeding direction. For this reason, at that time, the transport gear 7 also rotates in the reverse direction.

Thereafter, when the rotation of the conveying roller 1 is started, the first partial gear 12 is meshed with the conveying gear 7 rotating in the reverse direction, and a sudden load is generated. As a result, the load torque increases momentarily, the electromagnetic clutch provided in the drive source or the coupled drive mechanism slips, and the rotation timing of the roller or the like is delayed, resulting in poor paper feeding. In addition, the sudden load may cause abnormal noise or damage to the gear tooth surface.

Conventionally, as a method for solving such a problem, as a method, when the missing gear and the conveying gear mesh with each other, a method of performing a slow-up drive in which the drive is temporarily stopped and then slowly started up is proposed. However, such a method sacrifices productivity, and is unsuitable for the trend of speeding up in recent years.

Conventionally, as another solution, it has been known to provide a separation means for separating the conveyance roller and the separation roller when the missing gear and the conveyance gear mesh with each other, but this also significantly increases the cost. There was a problem.
The present invention has been made in view of the above-described problems. In the paper feed driving device, when the conveyance roller is started to rotate, the sudden load generated when the missing gear and the conveyance gear mesh with each other is alleviated, and the peak is provided. By reducing the load, a more stable paper feed driving device is provided.

A sheet feeding drive device according to the present invention includes a conveyance roller that is rotationally driven in a conveyance direction for conveying a sheet, a separation roller that is disposed in contact with the conveyance roller and is driven to rotate in a direction opposite to the conveyance direction, A conveying gear for driving the conveying roller; and a first toothless gear having a toothed portion for transmitting the driving gear driven from the driving source to the conveying gear and a toothless portion for blocking the toothed portion. In the paper feed drive
A second segmented gear having a segmented portion and a toothed portion, which is rotatably arranged coaxially with the first segmented gear, wherein the first segmented gear and the second segmented gear are energized. When the rotation of the first partial gear is started by being connected to the drive gear, the second partial gear connected by the urging means rotates, and the second partial gear The toothed portion of the gear first meshes with the conveyance gear, and after the rotation direction of the conveyance gear is set to the same direction as the rotation direction of the first partial gear, the first partial gear meshes with the conveyance gear. It is characterized by that.

The biasing means may be a tension coil spring.

According to the present invention, in the paper feed driving device, the transport roller 1 is driven by the reverse rotation of the separation roller 2 until the transport roller 1 is rotated by the transport gear 7 fixed coaxially, and in the direction opposite to the paper feed direction. Since the conveyor gear 7 also rotates in the reverse direction because it rotates while having a predetermined torque (depending on the retard torque limiter), when the tip of the second partial gear 13 meshes with the conveyor gear 7, The resistance is gradually changed to the forward meshing so that the reverse rotation speed of the transport gear 7 is gradually reduced, so that the impact generated at the time of the meshing can be reduced, and a more stable paper feed driving mechanism is provided. be able to.

1 is a schematic perspective view of a paper feed driving device according to an embodiment of the present invention. FIG. 2 is a schematic perspective view of the sheet feeding drive device according to the embodiment of the present invention, which is a rear view of FIG. 1. It is the schematic at the time of meshing | engagement start of the 2nd partial-tooth gear and conveyance gear of embodiment which concerns on this invention. It is the schematic at the time of meshing | engagement with the conveyance gear with the 1st partial gear of embodiment which concerns on this invention, and the 2nd partial gear. It is a schematic perspective view which shows the structure of a prior art.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic perspective view of an embodiment of a paper feed driving device according to the present invention.
FIG. 2 is a schematic perspective view of the embodiment of the present invention when a part is removed on the back side of FIG. 1.
Further, the same parts as those in FIG. 5 which is the prior art will be described with the same numbers.

The paper feed driving device shown in FIGS. 1 and 2 is arranged so as to face the conveyance roller 1 driven in the feeding direction and to be separated from the conveyance roller 1 and driven with a predetermined rotational torque in the direction opposite to the feeding direction. This is a paper feed driving device used in a paper feed separation device that feeds and separates a sheet material using a roller 2.

The paper feed driving device used in such a paper feed separating device reverses the rotation of the drive gear 6 connected to a main body motor (not shown) as a drive source via the idler gear 5 in the direction opposite to the paper feed direction. It is transmitted to the reverse gear 4 that rotates in the direction. On the other hand, the rotation of the drive gear 6 is transmitted to a conveyance gear 7 that intermittently rotates the conveyance roller 1 in the sheet feeding direction at a predetermined timing via a plurality of missing gears.

In more detail,
A sheet stored in a paper feed cassette or the like is conveyed toward a nip between the conveyance roller 1 and the separation roller 2 by a pickup roller (not shown).

The separation roller 2 rotates with a predetermined torque in a direction opposite to the paper feeding direction with a torque limiter 3 that generates a predetermined torque interposed therebetween. A reverse gear 4 fixed to the rotation shaft of the separation roller 2 is rotated from the drive gear 6 via an idler gear 5.

On the other hand, the conveyance roller 1 rotates in the paper feeding direction at a predetermined timing in response to the operation of the pickup roller on the upstream side in the sheet conveyance direction.

The intermittent rotation control is interposed between the drive gear 6 and the transport gear 7, and is used to transmit the drive from the drive gear 6 and the toothless portion for cutting off the drive from the drive gear 6. Conveying toothless gear 11 having a toothed portion, and configured to be coaxially integrated with the conveying toothless gear 11, and transmitting the drive with the toothless portion for blocking the driving gear 6 from being driven to the conveying gear 7. Engaged with a first toothless gear 12 having a toothed portion to be engaged and a engaging portion provided in the conveying toothless gear 11 to stop the conveying toothless gear 11 from rotating to a predetermined position, while operating In response to the electrical signal, the solenoid 8 that releases the engagement state, and the conveyance missing gear 11 that is caused by the operation of the solenoid 8 is released from the stopped state, and the conveyance missing gear 11 is moved from the stop position to the rotation direction. Rotation starting means 9 for rotating and meshing with the drive gear 6 is provided. That.

Furthermore, it is arranged coaxially in parallel with the conveying toothless gear 11 and the first toothless gear 12, and has a toothless part for interrupting driving to the conveying gear 7 and a toothed part for transmitting driving. A second partial gear 13 and a biasing means 20 having one end attached to the first partial gear 12 and the other end attached to the second partial gear 13 are provided.

Further, the biasing means 20 is arranged so that the top of the toothed portion of the second toothless gear 13 is in the state until the first toothless gear 12 and the second toothless gear 13 mesh with the conveying gear 7. A predetermined angle is urged in the rotational direction from the head of the toothed portion of the first toothless gear 12, and at the start of meshing with the transport gear 7, first, meshing is started from the second toothless gear 13, and gradually While reducing the reverse rotation speed of the transport gear 7 and meshing in the forward rotation direction, the phase shift with the first partial gear 12 is reduced against the biasing force of the biasing means 20, After the one-missing gear 12 is engaged, the conveying gear 7 is meshed with the first missing gear 12.

Here, the operation of rotating the transport roller 1 will be described.
First, when the solenoid 8 is energized at a predetermined timing according to the operation timing of the pickup roller, the conveying toothless gear 11 starts rotating by the urging force of the rotation starting means 9 and meshes with the drive gear 6. .

Next, the first missing gear 12 and the second missing gear 13 also rotate together with the conveying missing gear 11.
Thereafter, when a predetermined angle is rotated, the tip of the toothed portion of the second toothless gear 13 is first engaged with the transport gear 7.

At this time, the transport gear 7 rotates in the reverse direction, but the rotation of the second toothless gear 13 in the paper feeding direction is a rotation caused by the pulling of the biasing means 20, so that the reverse rotation is possible when meshing with the transport gear 7 It is.
For this reason, there is no possibility that an abrupt load is generated at the time of meshing. Thereafter, when the second partial gear 13 is engaged, the reverse rotational force of the transport gear 7 that is driven to rotate by the separation roller decreases, and finally starts to rotate in the forward rotation direction. Thereafter, the first partial gear 12 also meshes with the second partial gear 13 together with the conveyance gear 7, and the conveyance roller 1 is rotated via the conveyance gear 7.

Thus, although it is coaxial with the first partial gear 12 but is rotatable, the second partial gear 13 rotated together with the first partial gear 12 by the urging means 20 is first reversely rotated. The generation of a sudden load is prevented by meshing with the transporting gear 7 that is present.

When the sheet is conveyed for a predetermined distance, the meshing of the toothed portions of the first missing gear 12 and the second missing gear 13 with the conveying gear 7 is completed. After that, the conveying missing gear 11 also finishes meshing with the drive gear 6, and the hooking portion provided on the conveying missing gear 11 engages with the rotation starting means 9, so that the conveying missing gear 11 and the first missing gear 11 are engaged. The rotation of all of the tooth gear 12 and the second partial gear 13 is stopped.
The preferred embodiments of the present invention have been described above, but various modifications and changes other than those mentioned above can be made.

1 Transport roller
2 Separation roller
3 Torque limiter
4 Reverse gear
5 idler gear
6 Drive gear
7 Transport gear
8 Solenoid
9 Rotation starting means
11 Conveyor gear
12 First toothless gear
13 Second gear
20 Energizing means

Claims (2)

A conveyance roller that is rotationally driven in a conveyance direction for conveying the sheet;
A separation roller disposed in contact with the transport roller and driven to rotate in a direction opposite to the transport direction;
A transport gear for driving the transport roller;
In a paper feed driving device comprising a first toothless gear having a toothed portion for transmitting the drive of a driving gear driven from a driving source to the conveying gear and a toothless portion for blocking,
A second segmented gear having a segmented portion and a toothed portion, which is rotatably arranged coaxially with the first segmented gear;
The second toothless gear and the first toothless gear are connected by an urging means,
When the rotation of the first toothless gear starts to be coupled with the drive gear, the second toothless gear connected by the biasing means rotates, and the toothed portion of the second toothless gear first The paper feed drive is characterized in that the first partial gear engages with the conveyance gear after the conveyance gear is engaged with the conveyance gear and the rotation direction of the conveyance gear is set to the same direction as the rotation direction of the first partial gear. apparatus. 2. The sheet feeding drive device according to claim 1, wherein the biasing means is a tension coil spring.

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